Suggestions for the Series

Depends on how you want to talk about spinoffs. If SV hadn't gotten a sequel, I'd call it a spinoff - now, maybe you could call it a subseries or a series of spinoffs. It just depends.

It had a lot of holes way before Orochi. Burst just wasn't written well.

While I'm not looking at spoilers, I think it might be best not to put too much thought into this just yet. The Neptunia fanbase does this over things that have extremely simple answers and it's all really just speculation - until it's elaborated on or truly touched on in the games in some way, or never is at all, then I think maybe it might be better to leave it be?

Though I do remember there being talk of SK2 being placed somewhere in a timeline involving SV. Who's to say EV just doesn't take place after SK2 and it's as simple as that?

Regarding games with multiple storylines in themselves, if they don't tie together (like Sonic Adventure) then I don't know if I'd necessarily call those alternate universes unless the game pulls a BlazBlue or Higurashi regarding those specifically - they'll often either pick one to be the "true" end (as I think EV did with one of SV's?) or, come the next game, mesh them all together and imply a little of everything happened. Multiple storylines can just be used to have multiple storylines and are meant more to be what ifs or just other stories rather than anything overly significant.

I think it depends on how they do it. There's a lot of potential to do some really creative things with the idea, but it just depends on the execution. I'd say Neptunia is a great example of how it's done well, but people overthink it and lump things together there that shouldn't be.

Wasn't the Power Rangers equivalent really bad? Unless you mean Gokaiger to Sentai, that's got a good reputation. That said, I... dunno if I'd call Decade well received myself considering the reputation that has, but I guess it's popular enough to some - and Gokaiger is definitely liked enough. Though I'm not sure if anniversary crossovers can really be counted in the same category, to be fair, since those were done for special occasions? It's not like Mario being Smash makes Mario part of a multiverse, and with Kamen Rider, outside of Decade, one can easily make the argument all those things are self-contained on their own and the multiverse stuff only exists in a separate crossover "canon" anyway.

spin off.

Why ignore SK2 entirely would be stupid? Retcons exist

No game has ever acknowledged Bon Appetit, or the different versions told of the first Hebijo/Hanzo fight from the mangas or the version told by the anime.

And SK2 is a self contained story, Takaki said it himself

Not really, just pointing out that ignoring entries on the franchise isn't nothing new and the fact they did acknowledge SK2 on Estival means that they have some sort of plan in place.

About the multiverse thing and such, as you people are saying in videogames you can retcon everything, to introduce a new thematic, characters or tell a new storyline.

3DS games have their own story based heavily in storyline and characters past, and Vita games are more about the character interactions, using both as guide for the future games. 

One of the best examples are Megaman X games, the main storyline ends in X5 with the fight of X and Zero, within the elf wars and such ,jumping then at the Zero series ( This mean the canon storyline).

X6-X8 are the non canonical games at here, but serves as well as material for the future series, as the worst example is Axl that had the ability to copy the enemies and transform in them ,and only appeared in the non canonical series. Then happened something very strange at the ZX Advent series (that is canonical) ,when appeared the model "A" mostly of us thought that indeed was based in Axl with the same abilities and appearance, but ended being that was based in the final boss of the game and no in Axl directly. Also the biometal interections ( that are based in the spirits of the main X character series).

The thing is that in videogames can happen everything with the weirdest twists, using things for the different universes, adapting them for the next installements.

Finally Senran Kagura is a living thing trying to re-invent in every series, and that is why I do like between the 3ds and Vita games, are so different, but at the same time so similar, at each installment you are not feeling robbed, because these differences about the games.

Also,I do want Senran Kagura ZERO so bad, I do want to play with badass ninjas again ,with male and female characters. Strider and Ninja Gaiden games were cool!  and I am sure I will feel the same about this one with Hanzo and his group, but Takaki will never make it ,because muh Otaku pride and muh money, still I love you, bastard.

Also, I will post the most recent one along Senran Kagura with Pokemon ORAS. Caused a similar impact.

Outside of Bon Appetit, Senran Kagura has never been 100% comedic, specially everything related with the shinobi world, though.

Hello, I don't mean to but in, I am relatively new in terms of the frequency I post here, and I only just entered the topic, but I am surprised at all the dots people seem to have connected in terms of the multiple timelines.
Mostly because they to pretty much go hand-in-hand with the timeline I made.

There is alot of truth and logistics to what has been stated in regards to the multiple timelines in the series and personally I don't see any real problem with it.

It seems to only argument that has been made against it is that some people don't personally like the idea but that is completely irrelevant.

The series has shown us enough evidence to support that it is in fact a multiverse and no amount of personal displeasure to the notion invalidates that. Sorry if I come off as intrusive or rude, but I just wanted to throw in my 2 cents.

I really love the series and enjoy talking about it as much as I can.

Also, here is the timeline I had done.
It really isn't that complicated looking at it now.

Again To my surprise, it is quite accurate to what has been mentioned in the thread.